JP4639101B2 - Component supporting substrate, manufacturing method thereof, and optical device - Google Patents

Description

  The present invention relates to a component support substrate for supporting various components such as an optical component, a manufacturing method thereof, and an optical device including a component support substrate, an optical element, and an optical component.

  In recent years, with the development of information communication technology represented by the Internet and the dramatic improvement in the processing speed of information processing apparatuses, there is an increasing need for transmitting and receiving large-capacity data such as images. An information transmission speed of 10 Gbps or higher is desirable to exchange such a large amount of data freely through an information communication facility, and great expectations are placed on optical communication technology as a technology that can realize such a high-speed communication environment. On the other hand, signals can be transmitted at high speeds even on signal transmission paths at relatively short distances, such as connections between wiring boards in equipment, connections between semiconductor chips in wiring boards, connections within semiconductor chips, etc. It has been desired in recent years. For this reason, it is thought that it is ideal to shift from the conventionally common metal cable or metal wiring to optical transmission using an optical waveguide or the like.

  In recent years, various optical devices that include an optical waveguide, an optical element, a component support substrate, and the like and perform optical communication between the optical waveguide and the optical element have been proposed (see, for example, Patent Documents 1 and 2). However, the prior art described in Patent Documents 1 and 2 does not actively perform alignment between components, but only relies on a self-alignment action during solder reflow. Therefore, an optical axis shift is likely to occur between the optical element and the optical waveguide, and a light transmission loss is likely to occur.

Therefore, recently, not only the self-alignment optical device described above, but also a guide pin alignment optical device that positively aligns each component has been proposed (see, for example, Patent Document 3). An example of the improved form is shown in FIG. In this optical device 101, a guide pin 103, which is a component support, is erected on the component support substrate 102 side, and the optical waveguide 104 is fixed in an aligned state using the guide pin 103. More specifically, the component support substrate 102 is provided with a filling hole 105 having a circular cross section and a constant inner diameter. The filling hole 105 is filled with a resin material and cured to form a resin filling portion 106, and a fitting hole 107 is formed in the resin filling portion 106. A part of the guide pin 103 is fitted into the fitting hole 107 and fixed. On the other hand, an alignment hole 108 is provided in the optical waveguide 104 in advance. Then, the optical waveguide 104 is aligned with the component support substrate 102 and the optical element 110 by inserting the protruding portion of the guide pin 103 into the alignment hole 108.
JP 2002-236228 A JP-A-8-250542 Japanese Unexamined Patent Publication No. 2003-107283 (FIGS. 17, 19, etc.)

  However, the guide pin alignment optical device 101 has the following problems. That is, the component support substrate 102 is made of a ceramic material having a relatively small coefficient of thermal expansion or thermal shrinkage, whereas the resin filling portion 106 is made of a resin material having a relatively large coefficient of thermal expansion or thermal shrinkage. Therefore, when the optical device 101 is heated or cooled during use, the vicinity of the interface between the component support substrate 102 and the resin filling portion 106 (due to the difference in thermal expansion coefficient between them and the difference in thermal shrinkage) ( In particular, thermal stress is concentrated in the vicinity of the opening of the filling hole 105. As a result, as shown in FIG. 30, a gap 111 is generated between the component support substrate 102 and the resin filling portion 106, and the adhesion between the two deteriorates. Further, cracks 121 are likely to occur on the component support substrate 102 side or the resin filling portion 106 side. Therefore, in order to realize higher reliability than the conventional optical device 101 shown in FIG. 29, it is necessary to take some measures. Further, in the optical device 101 in which the gap 111 and the crack 121 are generated, the strength for holding the resin filling portion 106 in the filling hole 105 is reduced. For this reason, the guide pin 103 is displaced, and the alignment accuracy between the components may be deteriorated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a component support substrate that is excellent in reliability because of good adhesion of the resin-filled portion and that allows high-precision alignment between components. There is. Another object of the present invention is to provide an optical device that is excellent in reliability because of good adhesion of the resin-filled portion, and that has excellent optical transmission efficiency because high-precision optical axis alignment between components is possible. is there. Still another object of the present invention is to provide a production method suitable for obtaining the above excellent component support substrate.

As a first problem solving means for solving the above problems, a filling hole having a first main surface and a second main surface and having a first opening opening at least in the first main surface is provided. A fixed board by being fitted in the fitting hole, a resin filling portion having a fitting hole disposed in the filling hole and opening in the first main surface, and the fitting hole A part support that can support other parts at a location protruding from the inner surface, and the filling hole has a stepped unevenness on the inner wall surface, and the stepped unevenness is formed on the inner wall surface with the recess and the inner wall. There is a component support board characterized in that a height difference from a convex portion on a wall surface is 100 μm or more and has an inner diameter that varies depending on the depth position .

  Since the filling hole of the above prior art has a constant inner diameter, there are no irregularities on the inner wall surface, whereas there are irregularities on the inner wall surface of the filling hole of the first problem solving means. Therefore, according to the configuration of the first problem solving means, the contact area between the inner wall surface of the filling hole and the resin filling portion is increased, and the adhesion of the resin filling portion is improved. Therefore, even if thermal stress is concentrated in the vicinity of the interface between the component support substrate and the resin filling portion, no gaps or cracks are generated, and the reliability is excellent. Moreover, as a result of the resin-filled portion being firmly held in the filling hole, it is possible to prevent the component support member from being misaligned, and the alignment accuracy between the components is increased.

  The “other component” in the first problem solving means is, for example, a component configured separately from the component support substrate (for example, an optical component to be described later), and an object to be aligned with the component support substrate. It refers to things. However, the “other parts” are not essential components in the first problem solving means.

  Further, as a second problem solving means for solving the above problems, a component support board according to the first problem solving means, an optical element mounted on the component support board, and the optical element and position There is an optical device comprising an optical component supported by the component support in a combined state.

  Therefore, according to the second problem solving means, the contact area between the inner wall surface of the filling hole and the resin filling portion is increased, and the adhesion of the resin filling portion is improved. Therefore, even if thermal stress is concentrated in the vicinity of the interface between the component support substrate and the resin filling portion, no gaps or cracks are generated, and the reliability is excellent. In addition, as a result of the resin filling portion being firmly held in the filling hole, it is possible to prevent the positional deviation of the component support body and to perform high-precision optical axis alignment between the components. For this reason, the optical device excellent in optical transmission efficiency is realizable.

  As the substrate constituting the component support substrate, for example, a resin substrate, a ceramic substrate, a glass substrate or a metal substrate can be used, and a ceramic substrate is particularly preferable. When a ceramic substrate having a higher thermal conductivity than that of the resin substrate is used, the generated heat is efficiently dissipated. Therefore, for example, when applied to a component support substrate for supporting an optical component, a shift in emission wavelength due to deterioration of heat dissipation is avoided, and a component support substrate excellent in operational stability and reliability is realized. be able to. Preferable examples of such ceramic substrates include substrates made of alumina, aluminum nitride, silicon nitride, boron nitride, beryllia, mullite, low-temperature fired glass ceramic, glass ceramic and the like. Among these, it is particularly preferable to select a substrate made of alumina or aluminum nitride.

  Moreover, as a suitable example of a resin substrate, the board | substrate which consists of EP resin (epoxy resin), PI resin (polyimide resin), BT resin (bismaleimide-triazine resin), PPE resin (polyphenylene ether resin) etc. is mentioned, for example. Can do. In addition, a substrate made of a composite material of these resins and organic fibers such as glass fibers (glass woven fabric or glass nonwoven fabric) or polyamide fibers may be used. Preferable examples of the metal substrate include a copper substrate, a substrate made of a copper alloy, a substrate made of a single metal other than copper, and a substrate made of an alloy other than copper.

  The board constituting the component support board is preferably a wiring board provided with an insulating layer and a conductor layer (metal wiring layer), and particularly preferably a multilayer wiring board. The conductor layer may be formed on the substrate surface or may be formed inside the substrate. In order to achieve interlayer connection between these conductor layers, via hole conductors may be formed inside the substrate. For the conductor layer and via hole conductor, for example, a conductive metal paste made of gold (Au), silver (Ag), copper (Cu), platinum (Pt), tungsten (W), molybdenum (Mo), etc. is printed. Or it is formed by filling. An electric signal flows through such a conductor layer. In addition to such a wiring board, for example, it is allowed to use a build-up wiring board provided with a build-up layer formed by alternately laminating resin insulating layers and conductor layers on the board.

  The substrate constituting the component support substrate has a first main surface and a second main surface, and has a filling hole having at least a first opening opening at the first main surface. That is, the filling hole may be a non-through hole that opens only on the first main surface side, or may be a through hole that opens on both the first main surface side and the second main surface side. .

  The optical device of the second problem solving means includes an optical element mounted on a component support substrate. For example, one or more optical elements are mounted on a component support substrate. As the mounting method, for example, a method such as wire bonding or flip chip bonding, a method using an anisotropic conductive material, or the like can be employed. The optical element may be directly mounted on the component support substrate, or may be indirectly mounted via some member. As an optical element (that is, light emitting element) having a light emitting portion, for example, a light emitting diode (LED), a semiconductor laser diode (LD), a surface emitting laser (Vertical Cavity Surface Emitting Laser; VCSEL), etc. Can be mentioned. These light emitting elements have a function of converting an inputted electric signal into an optical signal and then emitting the optical signal from a light emitting unit toward a predetermined portion. On the other hand, examples of the optical element having a light receiving portion (that is, a light receiving element) include a pin photodiode (pin PD) and an avalanche photodiode (APD). These light receiving elements have a function of causing an optical signal to be incident on the light receiving unit, converting the incident optical signal into an electric signal, and outputting the electric signal. The optical element may have both a light emitting part and a light receiving part. Suitable materials used for the optical element include, for example, Si, Ge, InGaAs, GaAsP, GaAlAs and the like. Such an optical element (particularly a light emitting element) is operated by an operation circuit. The optical element and the operation circuit are electrically connected through, for example, a conductor layer (metal wiring layer) formed on the component support substrate.

  The optical device of the second problem solving means includes an optical component supported by a component support in a state of being aligned with the optical element. Here, the optical component means a component having at least one of a light transmission function, a light collection function, and a light reflection function. As a specific example, examples of the optical component having an optical transmission function include an optical waveguide and an optical fiber. In addition, the base material which supports an optical waveguide shall also correspond to the optical component which has an optical transmission function. An optical component composed of an optical fiber and an optical fiber connector that supports the optical fiber also corresponds to an optical component having an optical transmission function. Examples of the optical component having a condensing function include a lens component represented by a microlens array. As an optical component having a light reflection function, for example, there is an optical path conversion component. In addition, it can be said that the optical fiber connector in which the optical path changing part is formed is an optical component having a light reflecting function. It can be said that the optical waveguide in which the optical path conversion unit is formed is an optical component having an optical transmission function and an optical reflection function. Note that only one optical component may be supported on the component support substrate, or two or more optical components may be supported.

  The optical waveguide refers to a plate-like or film-like member having a core serving as an optical path through which an optical signal propagates and a clad surrounding the core. For example, an organic optical waveguide made of a polymer material, quartz glass, There are inorganic optical waveguides made of compound semiconductors and the like. As the polymer material, a photosensitive resin, a thermosetting resin, a thermoplastic resin, or the like can be selected. Specifically, a polyimide resin such as a fluorinated polyimide, an epoxy resin, a UV curable epoxy resin, a PMMA ( Polymethyl methacrylate), acrylic resins such as deuterated PMMA, deuterated fluorinated PMMA, polyolefin resins, and the like are suitable.

  A resin filling portion made of a resin material is disposed in the filling hole of the substrate. Since the resin material is excellent in workability compared to an inorganic material such as ceramic, high-accuracy drilling of the resin-filled portion can be performed easily and at low cost. The resin filling portion has a fitting hole that opens at the first main surface. The fitting hole may be a non-through hole that opens only on the first main surface side (that is, has one opening), or opens in both the first main surface and the second main surface (that is, the opening). It may be a through hole. The shape of the fitting hole is not particularly limited as long as it can support a component support described later. However, the fitting hole is preferably smaller in diameter than the filling hole. In addition, the center line of the filling hole and the center line of the fitting hole preferably match, but do not necessarily match.

  The resin forming the resin filling portion is not particularly limited, and for example, a thermosetting resin, a thermoplastic resin, a photosensitive resin, or the like can be used. Specific examples of the thermosetting resin include an epoxy resin, a polyimide resin, a fluorine resin, a bismaleimide resin, a phenol resin, a polyphenylene resin, a polyolefin resin, and a fluorine resin. In this case, it is preferable to select a thermosetting resin having a small amount of curing shrinkage. Specific examples of the thermoplastic resin include polysulfone (PSF), polyphenyl ether (PPE), polyphenylene sulfone (PPS), polyether sulfone (PES), polyphenylene sulfide (PPES), and the like.

  The resin filling part may contain a filler. The addition of the filler contributes to the reduction of the thermal expansion coefficient of the resin filling portion. Examples of the filler include an organic filler made of resin and the like, and an inorganic filler made of ceramic, metal, glass and the like. An advantage obtained when an organic filler is selected is that the fitting hole is easily processed. On the other hand, an advantage obtained when an inorganic filler is selected is that, for example, when a ceramic substrate is used, it is easy to match the thermal expansion coefficient of the resin-filled portion with the thermal expansion coefficient of the ceramic substrate. Furthermore, when a metal filler is selected, conductivity can be imparted to the resin-filled portion.

  The component support body which comprises a component support substrate is fixed by being fitted by the fitting hole. A part of the component support protrudes from at least the first main surface side, and another component (specifically, an optical component or the like) can be supported at the protruding portion. The shape of the component support is not particularly limited, but for example, a pin-shaped one (guide pin) is preferable, and the material is preferably a metal that is hard to some extent, such as stainless steel. In addition, the diameter of the component support (particularly the diameter of the protruding portion) needs to be approximately the same diameter as the alignment recess so that it can be fitted to the alignment recess of another component. In addition, although it does not specifically limit about the number of component support bodies, From a viewpoint of the improvement of positioning accuracy and the improvement of fixed intensity | strength, it is good that it is more than one.

  In this case, it is preferable that the fitting hole is a precision processing hole, specifically, a precision processing hole having a processing requirement accuracy within ± 0.001 mm. In this case, the alignment accuracy of each component can be improved. In particular, in an optical device, it is desirable to employ a precision machined hole. In this case, it is possible to align the optical axes of optical elements and optical components with high accuracy.

  The filling hole has irregularities on its inner wall surface. As for the unevenness provided on the inner wall surface of the filling hole, the height difference between the recess on the inner wall surface and the protrusion on the inner wall surface is preferably 100 μm or more, and particularly preferably 500 μm or more. That is, in the filling hole having a height difference of less than 100 μm, the contact area between the inner wall surface and the resin filling portion cannot be sufficiently secured, and the adhesion of the resin filling portion cannot be sufficiently improved. Here, the “concave portion” refers to a portion farthest from the central axis of the filling hole, and the “convex portion” refers to a portion closest to the central axis of the filling hole. Therefore, the “height difference between the concave on the inner wall surface and the convex on the inner wall surface” means the distance to the point farthest from the central axis of the filling hole and the point closest to the central axis of the filling hole. The difference from the distance. Therefore, the condition required for the filling hole is that it does not have a constant inner diameter, in other words, has an inner diameter that varies depending on its depth position. That is, the filling hole has a minimum diameter portion at a predetermined depth position and a maximum diameter portion at a different depth position.

  The maximum diameter of the filling hole is preferably 1.1 times or more of the minimum diameter, and more preferably 1.5 times or more. In this case, a sufficient contact area between the inner wall surface and the resin filling portion is ensured, and the adhesion of the resin filling portion is easily improved.

  The filling hole preferably has the largest diameter at the first opening. When it has the 2nd opening part opened on the 2nd principal surface, it is good for the hole for filling to have the largest diameter in at least any one of the 1st opening part and the 2nd opening part. With such a hole shape, it becomes easy to fill the resin material into the filling hole, and the occurrence rate of incomplete filling of the resin material is reduced. Further, even if air is mixed in the resin material, the air easily escapes to the outside, so that the residual ratio of bubbles in the resin filling portion is lowered. That is, such a hole shape is convenient for improving the adhesion of the resin-filled portion.

  The filling hole preferably has the smallest diameter at an intermediate position between the first opening and the second opening, and the diameter increases from the intermediate position toward the first opening and the second opening. Is particularly desirable. With such a hole shape, it is easier to further reduce the occurrence rate of incomplete filling and the bubble residual rate, and it is easy to process and form the filling hole itself.

For example, when the substrate is a ceramic multilayer substrate composed of a plurality of ceramic layers having through holes, the filling hole has a plurality of continuous through holes, and the first opening and the second opening from an intermediate position. It is particularly preferable to have a structure in which the diameter gradually increases toward the part. With such a hole shape, stress that tends to concentrate in the vicinity of the opening of the filling hole can be dispersed even in a portion where the diameter increases stepwise (that is, an edge portion). Therefore, stress concentration at a specific location can be avoided, and generation of a gap or crack that leads to a decrease in reliability can be reliably prevented.
In the case where the substrate is a ceramic multilayer substrate composed of a plurality of ceramic layers having through holes, the filling hole has a structure in which a plurality of the through holes arranged with a center axis shifted are continuous. May be. Even if it is such a hole shape, the unevenness | corrugation exists in the inner wall face of the hole for filling.

Further, as a third problem solving means for solving the above-described problem, a filling hole having a first main surface and a second main surface, and having a first opening opening at least in the first main surface. And a resin filling portion that is disposed in the filling hole and has a fitting hole that opens at the first main surface, and the fitting hole supports a component that can support other components. A protrusion provided on the body or the other part itself can be fitted, and the filling hole has a stepped unevenness on an inner wall surface thereof, and the stepped unevenness is formed with a recess on the inner wall surface and the There is a component support board characterized in that the height difference from the convex portion on the inner wall surface is 100 μm or more, and has an inner diameter that varies depending on the depth position .
Therefore, according to the configuration of the third problem solving means, the contact area between the inner wall surface of the filling hole and the resin filling portion is increased, and the adhesion of the resin filling portion is improved. Therefore, even if thermal stress is concentrated in the vicinity of the interface between the component support substrate and the resin filling portion, no gaps or cracks are generated, and the reliability is excellent. Further, as a result of the resin-filled portion being firmly held in the filling hole, it is possible to prevent the positional deviation of the projecting portions of the component support and other components, and the alignment accuracy between the components is increased.
The “other component” in the third problem solving means is, for example, a component (for example, an optical component) configured separately from the component support substrate, and the object to be aligned with the component support substrate. Refers to that. However, “other parts” are not essential components in the third problem solving means. Similarly, the “component supporter that can support other components” is not an essential component in the third problem solving means.

And as a 4th problem-solving means for solving the said subject, in the manufacturing method of the component support substrate concerning the 1st, 3rd problem-solving means, the through-hole from which a diameter differs in several ceramic unsintered bodies to form a, arranged a drilling step of the maximum diameter of the through hole in more than 1.1 times the minimum diameter, the ceramic green body diameter of the through-hole formed therein, the through hole of large diameter In a state where the ceramic unsintered body formed is placed outside, a multi-layer press-bonding step of laminating and press-bonding the plurality of ceramic unsintered bodies to produce the ceramic laminate having the filling holes, and A component supporting substrate comprising: a firing step of sintering the ceramic laminate to form the substrate; and a resin filling step of filling a resin material into the filling hole to form a resin filling portion. There is a manufacturing method.

  Therefore, according to the manufacturing method according to the fourth problem solving means, the component support board having excellent reliability and the like can be manufactured easily and at low cost.

  Hereinafter, the manufacturing method of the said component support substrate is demonstrated along a process.

  In the drilling step, through holes having different diameters are formed in a plurality of ceramic unsintered bodies. Since ceramic materials have the property of becoming extremely hard when completely sintered, processing becomes difficult and processing costs increase. However, since a non-sintered ceramic material that is not so hard is used as a processing target in this step, drilling can be performed relatively easily and at low cost. A well-known technique can be adopted as a hole processing method in the drilling step, and specific examples include drilling, punching, and laser processing. However, from the viewpoint of low cost, mechanical processing such as drilling or punching is preferable, and punching is particularly preferable.

  In the laminating and crimping process, when there are a plurality of through holes having different diameters, a ceramic unsintered body in which a relatively small diameter hole is formed compared to a large diameter through hole is disposed inside, and the small diameter through hole is disposed. A ceramic green body in which a through hole having a relatively larger diameter than the hole is formed is disposed outside. When this arrangement is adopted, a filling hole having a plurality of continuous through holes is formed. Moreover, it is preferable that the filling hole has a structure in which the diameter gradually increases from the intermediate position toward the first opening and the second opening. In this state, a plurality of ceramic green bodies are laminated and pressure-bonded to produce a ceramic laminate having filling holes.

  In the firing step, the unsintered ceramic laminate is sintered at a high temperature to form the substrate. At this point, the ceramic hardens. The firing temperature, firing time, etc. are appropriately set according to the type of ceramic selected.

  In the resin filling step, the resin filling portion is formed by filling the resin material into the filling holes. More specifically, after filling an uncured resin material into the filling hole, the resin material is cured to form a resin filling portion. For example, when a thermosetting resin is selected, the resin material is cured by heating after filling. When a photosensitive resin is selected, the resin material is cured by irradiating with ultraviolet rays after filling. The filling of the resin material can be performed by a technique such as printing. Moreover, as the resin material, an uncured resin material containing various fillers may be used, or an uncured resin material containing an inorganic filler having high thermal conductivity may be used. The reason is as described above.

  A fitting hole forming step may be further performed after the hole making step, the lamination pressure bonding step, the firing step, and the resin filling step. In the fitting hole forming step, a fitting hole is formed in the resin filling portion. A well-known technique can be employed as the hole drilling method in this step, but in this case, it is desirable to perform precision hole drilling. This is because, if the fitting hole is formed by such a processing method, the component support body which becomes a reference for alignment can be supported at a desired correct position. Specific methods for precision hole drilling include drilling, punching, and laser processing. In consideration of cost and the like, drilling using a precision drill is most preferable. You may finely adjust a hole diameter by performing a finishing process as needed after a fitting hole formation process.

  Instead of the above method of performing the fitting hole forming step after performing the resin filling step, for example, a method of simultaneously performing the resin filling step and the fitting hole forming step as follows may be employed. Specifically, first, a spacer member is disposed in the filling hole. As a suitable example of the spacer member, for example, there is a mold having pins. The pin has a shape corresponding to the shape of the fitting hole. In this case, the mold and the substrate should be aligned with high accuracy. In this state, after filling and curing the uncured resin material, the spacer member is removed. And even if it is this method, the resin filling part which has a fitting hole can be formed comparatively easily.

  Then, a component support body attachment process may be performed and a component support body may be fitted to a fitting hole, and a component support body may be supported on a board | substrate.

  Instead of the above method of sequentially performing the resin filling step, the fitting hole forming step, and the component support attachment step, for example, a method of simultaneously performing the resin filling step and the component support attachment step as follows is adopted. Also good. Specifically, first, a part of the component support is inserted and held in the filling hole. In this case, it is desirable to align the component support with high accuracy. It is more preferable to temporarily hold and fix a plurality of component supports using a predetermined holding jig. Next, in this state, an uncured resin material is filled in the filling hole and cured. As a result, the resin filling portion having the fitting hole is formed, and at the same time, the component support body can be fitted and supported in the fitting hole. The holding jig is removed after the resin material is cured. This method is also extremely advantageous for cost reduction.

[First Embodiment]

  Hereinafter, an optical device according to a first embodiment embodying the present invention will be described in detail with reference to FIGS.

  As shown in FIGS. 1 and 2, the optical device 41 of the present embodiment has a structure in which an optical element (VCSEL 14, photodiode 16) and an optical component (optical waveguide 31) are mounted on a component support substrate 10. The ceramic substrate 11 constituting the component support substrate 10 is a substantially rectangular plate member having an upper surface 12 (first main surface) and a lower surface 13 (second main surface). The ceramic substrate 11 is a so-called ceramic multilayer wiring board composed of a plurality of ceramic layers 51, 52, 53, 54, and 55, and includes a metal wiring layer (not shown) on the upper surface 12, the lower surface 13, and the inner layer. The ceramic substrate 11 also includes a via-hole conductor (not shown), and metal wiring layers having different layers are connected to each other through the via-hole conductor.

  In FIG. 2, a VCSEL 14 which is a kind of light emitting element is mounted on the left end of the upper surface 12 of the ceramic substrate 11 with the light emitting surface facing upward. The VCSEL 14 has a plurality of (here, four) light emitting units 15 arranged in a line in the light emitting surface. Accordingly, these light emitting portions 15 emit laser light having a predetermined wavelength in a direction orthogonal to the upper surface 12 of the ceramic substrate 11 (that is, the upward direction in FIG. 2). On the other hand, a photodiode 16 which is a kind of light receiving element is mounted on the right end of the upper surface 12 of the ceramic substrate 11 in FIG. 2 with the light receiving surface facing upward. The photodiode 16 has a plurality of (here, four) light receiving portions 17 arranged in a line in the light receiving surface. Therefore, these light receiving portions 17 are configured to easily receive laser light from the upper side to the lower side in FIG.

  Note that the terminals of the photodiode 16 and the VCSEL 14 are respectively joined to the metal wiring layer on the upper surface 12 of the ceramic substrate 11. In particular, the VCSEL 14 is electrically connected to an operation circuit IC (not shown) mounted on the upper surface 12 of the ceramic substrate 11 via the metal wiring layer.

  As shown in FIGS. 1 and 2, filling holes 21 are formed at a plurality of locations (here, 4 locations) in the ceramic substrate 11 so as to open at both the upper surface 12 and the lower surface 13 of the ceramic substrate 11. Yes. The filling hole 21 is not constant in inner diameter but varies depending on the depth position. For this reason, the inner wall surface of the filling hole 21 has irregularities. The details of the shape of the filling hole 21 will be described later.

  In this embodiment, two of the four filling holes 21 are arranged close to the VCSEL 14 and the remaining two are arranged close to the photodiode 16. The pair of filling holes 21 disposed in the vicinity of the VCSEL 14 are substantially collinear with the rows of the light emitting portions 15 and are disposed at positions sandwiching the rows of the light emitting portions 15 from both ends thereof. The pair of filling holes 21 arranged in the vicinity of the photodiode 16 are substantially on the same straight line as the row of the light receiving portions 17 and are arranged at positions sandwiching the row of the light receiving portions 17 from both ends thereof.

  A resin filling portion 22 is provided inside these filling holes 21, and a fitting hole 23 is provided at substantially the center of the resin filling portion 22. The fitting hole 23 is circular and has an equal cross-sectional shape, and is open on both the upper surface 12 and the lower surface 13 of the ceramic substrate 11. In the case of this embodiment, the diameter of the fitting hole 23 is smaller than the minimum diameter of the filling hole 21 and is set to about 0.7 mm. Inside the four fitting holes 23, a guide pin 24 (component support) made of stainless steel and having a circular cross section is fitted with one end protruding toward the upper surface 12 side. Specifically, in this embodiment, a guide pin “CNF125A-21” (diameter 0.699 mm) defined in JIS C 5981 is used.

  As shown in FIGS. 1 and 2, a rectangular optical waveguide 31 is disposed on the upper surface 12 side of the ceramic substrate 11. The optical waveguide 31 is formed so that its outer dimension is slightly smaller than that of the ceramic substrate 11. The base material 32 constituting the optical waveguide 31 has a core 33 and a clad 34 surrounding the core 33 from above, below, left and right. The core 33 substantially becomes an optical path through which the optical signal propagates. In the case of the present embodiment, the core 33 and the clad 34 are formed of transparent polymer materials having different refractive indexes, specifically, PMMA (polymethyl methacrylate) having different refractive indexes. The number of the cores 33 serving as the optical path is four, the same as the number of the light emitting units 15 and the light receiving units 17, and they are formed so as to extend linearly and in parallel. An inclined surface having an angle of 45 ° with respect to the longitudinal direction of the core 33 is formed at both ends of the core 33, and a thin film made of a metal capable of totally reflecting light is deposited on the inclined surface. Therefore, both ends of each core 33 are provided with optical path conversion mirrors 35 and 37 that reflect light at an angle of 90 °. Circular alignment holes 36 are formed through the four corners of the optical waveguide 31. These alignment holes 36 are set to have a diameter of about 0.7 mm corresponding to the size of the guide pin 24. Each guide pin 24 protruding from the ceramic substrate 11 is fitted in each alignment hole 36 (alignment recess) of the optical waveguide 31. As a result, the optical waveguide 31 is fixed in an aligned state on the upper surface 12 of the ceramic substrate 11. Here, the “aligned state” specifically means that each optical path conversion mirror 35 located on the left end side in FIG. 2 is directly above each light emitting unit 15, and each core 33 and each light emitting unit 15 is connected. A state in which the optical axes are aligned and a state in which each optical path conversion mirror 37 located on the right end side in FIG. 2 is directly above each light receiving portion 17 and the optical axes of each core 33 and each light receiving portion 17 are aligned. . In the present embodiment, the ceramic substrate 11 and the optical waveguide 31 are fixed to each other only by the fitting relationship between the alignment hole 36 and the guide pin 24.

  A general operation of the optical device 41 configured as described above will be briefly described.

  The VCSEL 14 and the photodiode 16 become operable by supplying power through the metal wiring layer of the ceramic substrate 11. When an electrical signal is output from the driver IC (not shown) on the ceramic substrate 11 to the VCSEL 14, the VCSEL 14 converts the input electrical signal into an optical signal (laser light), and then converts the optical signal to an optical path at the left end of the core 33. The light is emitted from the light emitting unit 15 toward the mirror 35 for use. The laser light emitted from the light emitting unit 15 enters from the lower surface side of the optical waveguide 31 and enters the optical path changing mirror 35 of the core 33. The laser light incident on the optical path changing mirror 35 changes its traveling direction by 90 °. For this reason, the laser beam propagates along the longitudinal direction inside the core 33. Then, the laser light reaching the right end of the core 33 is incident on an optical path conversion mirror 37 formed at the right end of the optical waveguide 31 this time. The laser light incident on the optical path changing mirror 37 changes its traveling direction by 90 °. For this reason, the laser light is emitted from the lower surface side of the optical waveguide 31 and is incident on the light receiving portion 17 of the photodiode 16. The photodiode 16 converts the received laser light into an electrical signal, and outputs the converted electrical signal to a receiver IC (not shown).

  Next, a method for manufacturing the optical device 41 having the above configuration will be described with reference to FIGS.

  First, an optical waveguide 31 is produced by a conventionally known method (see FIG. 3), and then alignment holes 36 are formed at the four corners by performing precision drilling on the waveguide 31 (see FIG. 4).

  Further, the ceramic substrate 11 is produced by the following procedure. A raw material slurry is prepared by uniformly mixing and kneading alumina powder, an organic binder, a solvent, a plasticizer, and the like, and this raw material slurry is used to form a sheet with a doctor blade device. 5 layers of sintered bodies are formed. Next, a predetermined portion of each green sheet 56 is punched to form a through hole 57 forming a part of the filling hole 21 and a via hole (not shown) (see FIG. 5). Since it is still unsintered at this stage, drilling can be performed relatively easily and at low cost. Thereafter, the via hole is filled with a metal paste, and the metal paste is printed on the surface of the green sheet 56.

  In the subsequent laminating and crimping step, the five green sheets 56 are laminated and arranged, and they are crimped and integrated using a press device, thereby producing a ceramic laminate 58 having the filling holes 21 (FIG. 6). reference). In the ceramic laminate 58 of FIG. 6, the metal wiring layers and via hole conductors are not shown and are omitted.

  Next, after performing a drying process, a degreasing process, etc. according to a well-known method, a baking process is further performed at the heating temperature (1650 degreeC-1950 degreeC) which an alumina can sinter. Thereby, the ceramic laminate 58 is sintered to form the ceramic substrate 11. At this point, the ceramic hardens and shrinks (see FIG. 7).

  In the subsequent resin filling step, the resin filling portion 22 is formed in the filling hole 21 as follows. First, with respect to 80 parts by weight of bisphenol F type epoxy resin (“Epicoat 807” manufactured by JER) and 20 parts by weight of cresol novolac type epoxy resin (“Epicoat 152” manufactured by JER), a curing agent (“2P4MZ manufactured by Shikoku Kasei Kogyo Co., Ltd.) -CN ") 5 parts by weight, 200 parts by weight of a silica filler (" TSS-6 "manufactured by Tatsumori) treated with a silane coupling agent (" KBM-403 "manufactured by Shin-Etsu Chemical Co., Ltd.), an antifoaming agent (" Sannopco " Berenol S-4 "). A resin material for filling is prepared by kneading this mixture with three rolls. That is, in this embodiment, an uncured resin material containing an inorganic filler in a thermosetting resin is used.

  Next, the ceramic substrate 11 is set in a printing apparatus, and a predetermined metal mask (not shown) is placed in close contact with the upper surface 12 thereof. In the metal mask, an opening is formed in advance at a location corresponding to the filling hole 21. The resin material is filled in each filling hole 21 by printing the resin material through such a metal mask. Then, after the printed ceramic substrate 11 is removed from the printing apparatus, it is heated at 120 ° C. for 1 hour, and the filled resin material is semi-cured to form the resin filling portion 22 (see FIG. 8). Here, the reason why the resin filling portion 22 is not completely cured is to perform hole processing in the next fitting hole forming step more easily.

  In the subsequent fitting hole forming step, a precision hole is formed using a precision drill to form a fitting hole 23 in the resin filling portion 22 (see FIG. 9). According to such a processing method, the guide pin 24 serving as a reference for optical axis alignment can be the fitting hole 23 that can be supported at a desired correct position. Here, the ceramic substrate 11 is set in a surface polishing apparatus, and the upper surface 12 and the lower surface 13 are polished. By this polishing, the excess resin protruding from the opening of the filling hole 21 and the resin adhering to the substrate surface are removed. When this polishing process is performed, the unevenness on the upper surface 12 of the ceramic substrate 11 is eliminated and the ceramic substrate 11 is flattened.

  Next, a main curing process is performed in which the ceramic substrate 11 is heated at 150 ° C. for 5 hours to completely cure the resin filling portion 22. Furthermore, finishing is performed by a well-known method, and fine adjustment is performed so that the hole diameter of the fitting hole 23 becomes 0.700 mm. Specifically, the accuracy required for processing at this time is ± 0.001 mm.

  Next, the VCSEL 14 and the photodiode 16 are mounted on the flattened upper surface 12 of the ceramic substrate 11 via an anisotropic conductive material (not shown) (see FIG. 10). As a result, a part of the metal wiring layer on the upper surface 12 of the ceramic substrate 11 and the connection terminals of the VCSEL 14 and the photodiode 16 are electrically connected. At this time, since the upper surface 12 is a flat surface without unevenness, the VCSEL 14 and the photodiode 16 are parallel to the upper surface 12.

  In the subsequent component support attachment process, the guide pin 24 is press-fitted into the fitting hole 23 using a dedicated jig or the like (see FIG. 11).

  In the subsequent alignment step, the guide pins 24 of the ceramic substrate 11 are fitted into the alignment holes 36 of the optical waveguide 31 (see FIG. 12). Thus, the optical waveguide 31 is supported and fixed to the ceramic substrate 11 while simultaneously performing the optical axis alignment of the optical waveguide 31 and the VCSEL 14 and the optical axis alignment of the optical waveguide 31 and the photodiode 16. As described above, the optical device 41 of the present embodiment shown in FIGS. 1 and 2 is completed.

  As described above, in the optical device 41 of the present embodiment, the inner wall surface of the filling hole 21 has irregularities. Therefore, the contact area between the inner wall surface of the filling hole 21 and the resin filling portion 22 is increased, and the adhesion of the resin filling portion 22 to the filling hole 21 is increased. Therefore, even if thermal stress is concentrated near the interface between the component support substrate 10 made of a ceramic material and the resin filling portion 22 made of a resin material, no gaps or cracks are generated, and excellent in reliability. It becomes. Further, as a result of the resin filling portion 22 being firmly held in the filling hole 21, it is possible to prevent the positional deviation of the guide pin 24, and to align the optical axes of each component with high accuracy. For this reason, the optical device 41 excellent in optical transmission efficiency is realizable.

  Next, some examples and comparative examples of this embodiment will be described with reference to FIGS.

Examples and Comparative Examples

(Preparation of test sample of Example 1)

  Here, the test sample shown in FIG. 13 was produced according to the following procedure. First, five green sheets 56 are prepared, one of which is formed with a through hole 57 having an inner diameter of 1.20 mm, two of which are formed with a through hole 57 having an inner diameter of 2.00 mm, and the remaining two are 2 A 30 mm through hole 57 was formed. The green sheets 56 with the inner diameter 2.00 mm are formed on both sides of the green sheet 56 with the inner diameter 1.20 mm. The green sheet 56 has an inner diameter of 2.30 mm. A green sheet 56 in which holes 57 were formed was disposed. In this state, five green sheets 56 were laminated and pressure-bonded, and then a firing process and the like were performed. As a result, a ceramic substrate 11 having a filling hole 21 having a structure in which five through holes 57 are continuous was obtained. Further, the resin filling portion 22 was formed by filling the ceramic substrate 11 with the above resin material and completely curing it.

  As a result, a test sample (test sample of Example 1) of the ceramic substrate 11 including the five ceramic layers 51 to 55 having the through holes 57 was obtained. In this test sample, the thickness of each ceramic layer 51 to 55 is set to about 0.24 mm, and the thickness of the entire ceramic substrate 11 is set to about 1.20 mm. The inner diameter of the through hole 57 included in the first ceramic layer 51 is set to about 1.9 mm. The inner diameter of the through hole 57 included in the second ceramic layer 52 is set to about 1.65 mm. The inner diameter of the through hole 57 included in the third ceramic layer 53 is set to about 1.0 mm. The inner diameter of the through hole 57 included in the fourth ceramic layer 54 is set to about 1.65 mm. The inner diameter of the through hole 57 included in the fifth ceramic layer 55 is set to about 1.9 mm.

Therefore, the filling hole 21 of the first embodiment has the largest diameter at the first opening 61 and the second opening 62 and the smallest at the intermediate position 63 between the first opening 61 and the second opening 62. ing. Further, the filling hole 21 according to the first embodiment has a structure in which the diameter gradually increases from the intermediate position 63 toward the first opening 61 and the second opening 62. In other words, the inner diameter of the filling hole 21 varies depending on the depth position, and the inner wall surface has irregularities.
(Preparation of test sample of Example 2)

  Here, the green sheets 56 with the inner diameter 2.00 mm are formed on both sides of the green sheet 56 with the inner diameter 2.30 mm and the inner diameter 1.20 mm. A green sheet 56 in which through holes 57 were formed was disposed. After performing the lamination | compression-bonding process in this state, the baking process, the resin filling process, etc. were implemented. As a result, a test sample (test sample of Example 2) of the ceramic substrate 11 having a thickness of about 1.20 mm having the filling holes 21 as shown in FIG. 14 was obtained.

  In the obtained test sample of Example 2, the inner diameter of the through hole 57 included in the first ceramic layer 51 is set to about 1.0 mm. The inner diameter of the through hole 57 included in the second ceramic layer 52 is set to about 1.65 mm. The inner diameter of the through hole 57 included in the third ceramic layer 53 is set to about 1.9 mm. The inner diameter of the through hole 57 included in the fourth ceramic layer 54 is set to about 1.65 mm. The inner diameter of the through hole 57 included in the fifth ceramic layer 55 is set to about 1.0 mm.

Therefore, the filling hole 21 of the second embodiment has the smallest diameter at the first opening 61 and the second opening 62 and the largest diameter at the intermediate position 63 between the first opening 61 and the second opening 62. ing. Further, the filling hole 21 according to the first embodiment has a structure in which the diameter gradually decreases from the intermediate position 63 toward the first opening 61 and the second opening 62. That is, the filling hole 21 also has an inner diameter that varies depending on the depth position, and has an uneven surface on the inner wall surface.
(Preparation of test sample of Example 3)

  Here, the test sample shown in FIG. 15 was produced according to the following procedure. First, five green sheets 56 were prepared, and through holes 57 having an inner diameter of 2.00 mm were formed for each. Then, five green sheets 56 were laminated and pressure-bonded in a state where the through-holes 57 were arranged with the center axis shifted. The shift amount (offset amount) in this case was set within the range of 0.30 mm to 0.50 mm. Then, a firing process, a resin filling process, and the like were performed to obtain a test sample (test sample of Example 3) of the ceramic substrate 11 having a filling hole 21 and a thickness of about 1.20 mm.

In the obtained test sample of Example 3, the inner diameters of the through holes 57 included in the ceramic layers 51 to 55 are all set to about 1.65 mm. That is, the filling hole 21 also has an inner diameter that varies depending on the depth position, and has an uneven surface on the inner wall surface.
(Preparation of test sample of Example 4)

  Here, the green sheets 56 with the inner diameter of 3.00 mm are disposed on both sides of the green sheet 56 with the inner diameter of 2.00 mm and the inner diameter is 2.00 mm. A green sheet 56 in which through holes 57 were formed was disposed. After performing the lamination | compression-bonding process in this state, the baking process, the resin filling process, etc. were implemented. As a result, a test sample (test sample of Example 4) of the ceramic substrate 11 having a thickness of about 1.20 mm having the filling holes 21 as shown in FIG. 16 was obtained.

  In the obtained test sample of Example 4, the inner diameter of the through hole 57 included in the first ceramic layer 51 is set to about 1.65 mm. The inner diameter of the through hole 57 included in the second ceramic layer 52 is set to about 2.48 mm. The inner diameter of the through hole 57 included in the third ceramic layer 53 is set to about 1.65 mm. The inner diameter of the through hole 57 included in the fourth ceramic layer 54 is set to about 2.48 mm. The inner diameter of the through hole 57 included in the fifth ceramic layer 55 is set to about 1.65 mm.

Therefore, the filling hole 21 of the fourth embodiment has the smallest diameter at the first opening 61 and the second opening 62 and the largest at the intermediate position 63 between the first opening 61 and the second opening 62. It is getting smaller. The filling hole 21 also has an inner diameter that varies depending on the depth position, and has an uneven surface on the inner wall surface.
(Preparation of test sample of Example 5)

  Here, the green sheet 56 with the inner diameter 2.00 mm is formed on both sides of the green sheet 56 with the inner diameter 3.00 mm and the inner diameter 3.00 mm. A green sheet 56 in which through holes 57 were formed was disposed. After performing the lamination | compression-bonding process in this state, the baking process, the resin filling process, etc. were implemented. As a result, a test sample (test sample of Example 5) of the ceramic substrate 11 having a thickness of about 1.20 mm having the filling holes 21 as shown in FIG. 17 was obtained.

  In the obtained test sample of Example 5, the inner diameter of the through hole 57 included in the first ceramic layer 51 is set to about 2.48 mm. The inner diameter of the through hole 57 included in the second ceramic layer 52 is set to about 1.65 mm. The inner diameter of the through hole 57 included in the third ceramic layer 53 is set to about 2.48 mm. The inner diameter of the through hole 57 included in the fourth ceramic layer 54 is set to about 1.65 mm. The inner diameter of the through hole 57 included in the fifth ceramic layer 55 is set to about 2.48 mm.

Therefore, the filling hole 21 of the fifth embodiment has the largest diameter at the first opening 61 and the second opening 62 and the largest diameter at the intermediate position 63 between the first opening 61 and the second opening 62. It is getting bigger. The filling hole 21 also has an inner diameter that varies depending on the depth position, and has an uneven surface on the inner wall surface.
(Preparation of test sample of Example 6)

  Here, three green sheets 56 each having a through hole 57 having an inner diameter of 2.00 mm are overlapped, and the green sheets 56 having a through hole 57 having an inner diameter of 3.00 mm are disposed on both sides thereof. After performing the lamination | compression-bonding process in this state, the baking process, the resin filling process, etc. were implemented. As a result, a test sample (test sample of Example 6) of the ceramic substrate 11 having a thickness of about 1.20 mm having the filling holes 21 as shown in FIG. 18 was obtained.

  In the obtained test sample of Example 6, the inner diameter of the through hole 57 included in the first ceramic layer 51 is set to about 2.48 mm. The inner diameters of the through holes 57 included in the second, third, and fourth ceramic layers 52, 53, and 54 are set to about 1.65 mm. The inner diameter of the through hole 57 included in the fifth ceramic layer 55 is set to about 2.48 mm.

Therefore, the filling hole 21 of Example 6 has the largest diameter at the first opening 61 and the second opening 62 and the largest diameter at the intermediate position 63 between the first opening 61 and the second opening 62. It is getting bigger. The filling hole 21 also has an inner diameter that varies depending on the depth position, and has an uneven surface on the inner wall surface.
(Preparation of test sample of Comparative Example 1)

Here, five green sheets 56 having an inner diameter of 1.20 mm formed with through holes 57 were placed one on top of the other and the lamination pressure bonding process was performed, followed by the firing process, the resin filling process, and the like. As a result, a test sample (test sample of Comparative Example 1) of the ceramic substrate 11 having a thickness of about 1.20 mm having the filling holes 21 as shown in FIG. 19 was obtained. In the obtained test sample of Comparative Example 1, the inner diameter of the through hole 57 included in each ceramic layer 51, 52, 53, 54, 55 is set to about 1.0 mm. Therefore, the filling hole 21 of Comparative Example 1 has a constant inner diameter regardless of the depth position, and has no irregularities on the inner wall surface.
(Preparation of test sample of Comparative Example 2)

Here, five green sheets 56 with through holes 57 having an inner diameter of 3.00 mm were placed in an overlapped manner and subjected to a laminating and crimping step, followed by a firing step, a resin filling step, and the like. As a result, a test sample (test sample of Comparative Example 2) of the ceramic substrate 11 having a thickness of about 1.20 mm having the filling holes 21 as shown in FIG. 19 was obtained. In the obtained test sample of Comparative Example 2, the inner diameter of the through hole 57 included in each ceramic layer 51, 52, 53, 54, 55 is set to about 2.48 mm. Therefore, the filling hole 21 of Comparative Example 2 also has a constant inner diameter regardless of the depth position, and has no irregularities on the inner wall surface.
(First test method and results)

  Here, first, test samples of Examples and Comparative Examples (excluding Example 3) were analyzed by a finite element analysis method, and the distribution state of thermal stress generated at the time of temperature change was simulated. Specifically, a two-dimensional linear finite element analysis model was created using a commercially available linear finite element analysis program. In order to simplify the analysis, the axis target model centered on the central axis of the filling hole 21 was used as the linear finite element analysis model. Further, 150 ° C., which is the curing temperature of the resin material, was set as a stress-free reference temperature, and temperature load was set so that the entire analysis model was 25 ° C. In creating the analysis model, the Young's modulus of alumina, which is the material of the ceramic substrate 11, was defined as 270 GPa, the Poisson's ratio was 0.25, and the thermal expansion coefficient was 6.5 ppm / K. The epoxy resin that is the material of the resin filling portion 22 was defined as Young's modulus of 6 GPa, Poisson's ratio of 0.33, and thermal expansion coefficient (CTE) of 15 ppm / K to 45 ppm / K.

  As a result, for example, when the CTE is 45 ppm / K, the value of the maximum equivalent stress that will be applied to the ceramic substrate 11 is about 195 MPa in Example 1, about 410 MPa in Example 2, about 350 MPa in Example 4, and Example 5 was about 220 MPa, Example 6 was about 225 MPa, and Comparative Example 1 was about 280 MPa. That is, the result that the thing with the largest diameter in the 1st opening part 61 and the 2nd opening part 62 (Example 1, 5, 6) is structurally preferable was obtained (refer the table | surface of FIG. 20). When the CTE was 15 ppm / K or more, the maximum equivalent stress value was increased in proportion to the CTE in any of the examples.

Further, in any sample, it was found that thermal stress was concentrated in the vicinity of the opening of the filling hole 21, particularly in the opening edge of the filling hole 21. However, it was also found that in each Example in which the inner wall surface of the filling hole 21 has a step portion, thermal stress is dispersed in the step portion. Therefore, in each Example, it was estimated that the thermal stress concentrated on the opening edge of the filling hole 21 was not as great as that of Comparative Example 1.
(Method and result of the second test)

  Next, the actually produced samples of Examples and Comparative Examples were cut along the thickness direction, and the cut surfaces were observed with an optical microscope. The degree of occurrence of gaps and cracks, the degree of remaining bubbles in the resin filling portion 22, and the degree of incomplete filling of the resin material were investigated. The results are shown in the table of FIG.

As a result, in Example 1, the resin material was completely filled in the filling hole 21. Further, no gaps or cracks were generated, and almost no bubbles remained. In Example 2, the filling of the resin material in the filling hole 21 was incomplete. Also, no gaps or cracks occurred, but some bubbles remained. In Example 3, the resin material was completely filled in the filling hole 21. Further, no gaps or cracks were generated, and only a few bubbles remained. In Example 4, the filling of the resin material in the filling hole 21 was incomplete. Also, no gaps or cracks occurred, but some bubbles remained. In Example 5, the resin material was completely filled in the filling hole 21. Also, no gaps or cracks occurred, but some bubbles remained. In Example 6, the filling material 21 was completely filled with the resin material. Further, no gaps or cracks were generated, and only a few bubbles remained. In Comparative Example 1, the resin material was completely filled in the filling hole 21 and no bubbles remained, but a gap was generated at the interface between the resin material and the ceramic material. In Comparative Example 2, the resin material was completely filled in the filling hole 21 and no bubbles remained, but cracks were generated at locations around the filling hole 21 on the ceramic substrate 11 side.
(Method and result of third test)

  Next, a leak test for investigating the presence or absence of minute gaps or cracks was performed by the following two methods on the test samples of the above examples and comparative examples (excluding Examples 2 and 4). That is, in the helium leak test as the first method, the front and back surfaces of the test sample were separated, and helium was supplied to one side surface to examine whether the helium leaked to the other side surface. In the red check test as the second method, a red solution was put on one side of the test sample, and it was investigated whether the red solution leaked on the opposite side. The results are shown in the table of FIG.

As a result, in Examples 1, 3, 5, and 6, neither helium leak nor red solution leak was observed. Therefore, it was found that even minute gaps and cracks did not occur. On the other hand, in Comparative Example 1 in which gaps and cracks occurred, helium leak and red solution leak were observed.
(Conclusion)

When the results of the above various tests were combined, it was found that Examples 1, 3, and 6 were superior to the others, and that Example 1 was particularly superior among them.
[Second Embodiment]

  FIG. 21 shows an optical device 71 according to a second embodiment that embodies the present invention. Here, differences from the first embodiment will be described, and the same points will only be denoted by common member numbers.

As shown in FIG. 21, the optical device 71 includes an optical fiber connector 72. This optical fiber connector 72 is a so-called MT connector provided at the tip of an optical fiber 75 having a four-core structure. The end face of the optical fiber 75 (that is, the end of each core 33) is exposed at the lower end face of the optical fiber connector 72. A pair of alignment holes 74 that open at the lower end surface are provided at both ends of the lower end surface of the optical fiber connector 72. The guide pins 24 on the ceramic substrate 11 side are fitted into these alignment holes 74. As a result, the optical fiber connector 7 2 on the left, with the VCSEL14 the optical axis suits, are fixed to the upper surface 12 side of the ceramic substrate 11. The right optical fiber connector 72 is fixed to the upper surface 12 side of the ceramic substrate 11 with the optical axis aligned with the photodiode 16.

Also in this optical device 71, the filling hole 21 having the same structure as that of Example 1 of the first embodiment is formed in the ceramic substrate 11. That is, there are irregularities on the inner wall surface of the filling hole 21, and thus the adhesion of the resin filling portion 22 to the filling hole 21 is improved. Therefore, even if thermal stress is concentrated near the interface between the component support substrate 10 made of a ceramic material and the resin filling portion 22 made of a resin material, no gaps or cracks are generated, and excellent in reliability. It becomes. Further, as a result of the resin filling portion 22 being firmly held in the filling hole 21, it is possible to prevent the positional deviation of the guide pin 24, and to align the optical axes of each component with high accuracy. For this reason, the optical device 71 excellent in optical transmission efficiency is realizable.
[Third Embodiment]

  FIG. 22 shows an optical device 81 according to a third embodiment that embodies the present invention. Here, the points that are different from the first embodiment will be described, and the same points are only given common member numbers.

  As shown in FIG. 22, the optical device 81 of the present embodiment includes a VCSEL 14 (optical element), a ceramic substrate 11 (substrate), a microlens array 87, an optical fiber connector 86, a guide pin 24 (component support), and the like. It is configured.

  A metal wiring layer 93 is formed on the upper surface 12 of the ceramic substrate 11, and a connection pad 92 is formed on a part of the metal wiring layer 93. A plurality of solder bumps 95 are provided on the lower surface 13 of the ceramic substrate 11. A VCSEL 14 is mounted on the upper surface 12 of the ceramic substrate 11. In place of the VCSEL 14, a light receiving element such as a photodiode may be mounted. An operation circuit IC 94 (so-called driver IC) for driving the VCSEL 14 is disposed in the vicinity of the VCSEL 14.

  The microlens array 87 disposed on the upper surface 12 side of the ceramic substrate 11 includes a lid-shaped microlens array main body 96. The microlens array body 96 is a resin molded product, and a microlens 88 is attached to the microlens mounting hole 90. The microlens array main body 96 has an alignment hole 89 formed so as to penetrate the front and back sides. The guide pin 24 is inserted into the alignment hole 89. It can be understood that the microlens array 87 of the present embodiment is an optical component having a light collecting function. The microlens 88 and the microlens array main body 96 may be configured as separate bodies as described above, but may be configured as a single body.

An optical fiber connector 86 disposed on the upper side of the microlens array 87 is attached to the tip of the optical fiber 82. A notch 85 having an inclined surface of about 45 ° is provided at the lower left side of the optical fiber connector 86, and an optical path conversion mirror 84 is formed on the inclined surface. The optical fiber connector 86 of the present embodiment in which the optical path conversion mirror 84 is formed can be grasped as an optical component having a light reflection function. The optical fiber connector 86 has an alignment hole 83 formed so as to penetrate the front and back sides. Guide pin 24 is inserted through the alignment holes 8 3.

  Also in this optical device 81, the filling hole 21 having the same structure as that of Example 1 of the first embodiment is formed in the ceramic substrate 11. Therefore, the inner wall surface of the filling hole 21 has irregularities, and therefore the adhesion of the resin filling portion 22 to the filling hole 21 is high. Therefore, even if thermal stress is concentrated near the interface between the component support substrate 10 made of a ceramic material and the resin filling portion 22 made of a resin material, no gaps or cracks are generated, and excellent in reliability. It becomes. Further, as a result of the resin filling portion 22 being firmly held in the filling hole 21, it is possible to prevent the positional deviation of the guide pin 24, and to align the optical axes of each component with high accuracy. For this reason, the optical device 81 excellent in optical transmission efficiency can be realized.

  In addition, you may change embodiment of this invention as follows.

-Although it is a form of the reference example instead of the form which belongs to this invention, it is also possible to form the hole 21 for filling with the method different from the said 1st-3rd embodiment , for example. First, a green sheet 56 as shown in FIG. 23 is prepared. Drilling is performed on one side surface (for example, the upper surface 12) of the green sheet 56 to form a mortar-shaped hole 98 (see FIG. 24). The mortar-shaped hole 98 formed in this case has an inner diameter that gradually decreases from the opening toward the bottom. Next, drilling is similarly performed on the opposite side surface (for example, the lower surface 13) of the green sheet 56 to form a mortar-shaped hole 98 (see FIG. 25). At this time, if the mortar-shaped holes 98 on both sides are communicated with each other inside the ceramic substrate 11, a suitable hole shape can be realized relatively easily.

  Further, after preparing a green sheet 56 and drilling the green sheet 56 to form a through hole, the openings on both sides of the through hole are expanded using a forming jig having a tapered surface. May be. Also by this method, a suitable hole shape can be realized relatively easily.

  -In the said embodiment, although board | substrate thickness is 1.20 mm, if board | substrate thickness is 0.3 mm or more, it can fully function as a board | substrate for supporting components. If the configuration of the present embodiment is adopted particularly when the substrate thickness is 1.0 mm or more, a component support substrate with higher reliability can be obtained.

  In the above embodiment, the method of performing the main curing (main curing) of the resin filling portion 22 after drilling the semi-cured resin filling portion 22 with a drill is employed, but the method of performing the main curing before drilling with the drill. Is preferably adopted. According to this method, since the change of the diameter of the fitting hole 23 due to the heat of the present cure can be prevented, the components can be aligned with higher accuracy. In addition, it is preferable to carry out a polishing step for smoothing the end surface of the resin filling portion 22 that is a surface to be processed before the present curing step. This is because if the end surface of the resin-filled portion 22 is smoothed by polishing, precision machining with a drill is facilitated.

In the above embodiment, the component support board 10 having a structure in which the component support (guide pin 24) is fitted and fixed in the fitting hole 23 is shown, but the component support board 10 does not necessarily have the component support. Also good. In other words, the component support may not be an element on the component support substrate 10 side but may be an element on the other component side configured separately from the component support substrate 10. An optical device 141 according to another embodiment shown in FIG. 26 basically includes the optical fiber connector 86 shown in FIG. The optical fiber connector 86 is provided with an alignment hole 83, and a guide pin 24 as a component support is fitted and fixed in the alignment hole 83. One end of the guide pin 24 protrudes from the lower surface side of the optical fiber connector 86 by a predetermined amount. On the other hand, the VCSEL 14 is mounted on the upper surface 12 side of the ceramic substrate 11 constituting the component support substrate 150. The filling hole 21 in the ceramic substrate 11 has the same structure as that shown in FIG. A resin filling portion 22 is provided inside the filling hole 21, and a fitting hole 23 is provided at substantially the center thereof. Then, by fitting and fixing the guide pin 24 in the fitting hole 23, the component support substrate 150 and the optical fiber connector 86 are aligned, and the optical device 141 is completed.
In the case of the optical device 151 of another embodiment shown in FIG. 27, the alignment hole 83 is not formed in the optical fiber connector 86. Instead, the alignment projection 124 is joined to the lower surface of the optical fiber connector 86 using an adhesive or the like. Then, by fitting and fixing the protrusion 124 in the fitting hole 23, the component support substrate 150 and the optical fiber connector 86 are aligned, and the optical device 151 is completed. Also in the optical device 161 of another embodiment shown in FIG. 28, the alignment hole 83 is not formed in the optical fiber connector 86. Instead, an alignment protrusion 224 is integrally formed on the lower surface of the optical fiber connector 86 itself. Then, by fitting and fixing the protrusion 224 in the fitting hole 23, the component support substrate 150 and the optical fiber connector 86 are aligned, and the optical device 161 is completed. Of course, instead of the filling hole structure shown in FIGS. 26, 27, and 28, for example, the filling hole structure shown in FIG. 14, FIG. 15, FIG. 16, FIG. 17, or FIG. Is possible.

Next, the technical ideas grasped by the embodiment described above are listed below.
(1) A substrate having a first main surface and a second main surface and having a filling hole having a first opening opening at least on the first main surface; and being disposed in the filling hole, A resin-filled portion having a fitting hole that opens on the first main surface, and a component support that can be fixed by being fitted into the fitting hole and can support other components at a location protruding from the fitting hole. And the filling hole has an inner diameter that varies depending on a depth position.

  (2) A substrate having a first main surface and a second main surface, and having a filling hole having a first opening opening at least in the first main surface; and being disposed in the filling hole, A resin-filled portion having a fitting hole that opens on the first main surface, and a component support that can be fixed by being fitted into the fitting hole and can support other components at a location protruding from the fitting hole. And the filling hole does not have a constant inner diameter, and the difference between the maximum diameter and the minimum diameter is 100 μm or more.

  (3) A filling hole having a first main surface and a second main surface, the first opening opening at the first main surface and the first opening opening at the second main surface. Fixed by being fitted in the fitting hole with a ceramic substrate, a resin filling portion disposed in the filling hole and having a fitting hole opened in the first main surface and the second main surface. And a part support that can support other parts at a location protruding from the fitting hole, and the inner wall surface of the filling hole has irregularities having a size of 100 μm or more. Component support board to be used.

  (4) Technical thoughts (1) to (3) The component support board according to any one of (1) to (3), an optical element mounted on the component support board, and the component in a state aligned with the optical element An optical device comprising an optical component supported by a support.

  (5) The ceramic substrate is a ceramic multilayer substrate composed of a plurality of ceramic layers having through holes, and the filling hole has a structure in which a plurality of the through holes arranged with a center axis shifted are continuous. The component support board according to the technical idea (3), wherein:

  (6) In the method for manufacturing a component support board described in the technical idea (5), a drilling step of forming a through hole in a plurality of ceramic unsintered bodies, and the through hole are arranged with their center axes shifted. Laminating and pressure-bonding the plurality of ceramic unsintered bodies in a state to produce a ceramic laminate having the filling holes, and firing the ceramic laminate to sinter the ceramic substrate; And a resin filling step of filling the hole for filling with a resin material to form the resin filling portion.

  (7) A substrate having a first main surface and a second main surface and having a filling hole having a first opening opening at least on the first main surface, and being disposed in the filling hole, And a resin filling portion having a fitting hole opened in the first main surface, and a fitting provided on the component support body or the other component itself capable of supporting another component is fitted in the fitting hole. The component supporting board, wherein the filling hole has an inner diameter that varies depending on a depth position.

  (8) a substrate having a first main surface and a second main surface, and having a filling hole having a first opening opening at least in the first main surface; and disposed in the filling hole, And a resin filling portion having a fitting hole opened in the first main surface, and a fitting provided on the component support body or the other component itself capable of supporting another component is fitted in the fitting hole. The component support board, wherein the filling hole does not have a constant inner diameter, and a difference between the maximum diameter and the minimum diameter is 100 μm or more.

  (9) having a first main surface and a second main surface, and having a filling hole having a first opening opening at the first main surface and a first opening opening at the second main surface. A ceramic substrate; and a resin filling portion disposed in the filling hole and having a fitting hole opened in the first main surface and the second main surface. A protrusion provided on a supportable component support or the other component itself can be fitted, and the inner wall surface of the filling hole has an unevenness having a size of 100 μm or more. Component support board to be used.

1 is a schematic plan view showing an optical device according to a first embodiment embodying the present invention. FIG. 2 is a schematic sectional view showing the optical device. FIG. 3 is a schematic cross-sectional view showing an optical waveguide in the manufacturing process of the optical device. FIG. 3 is a schematic cross-sectional view showing a state in which an alignment hole is formed in the optical waveguide in the manufacturing process of the optical device. FIG. 3 is a schematic cross-sectional view showing a state in which through holes are formed in a plurality of green sheets in the manufacturing process of the optical device. FIG. 3 is a schematic cross-sectional view showing a ceramic laminate having a filling hole in the manufacturing process of the optical device. FIG. 3 is a schematic cross-sectional view showing a state in which a ceramic laminate is fired to form a ceramic substrate in the manufacturing process of the optical device. FIG. 3 is a schematic cross-sectional view illustrating a state in which a resin filling portion is formed by filling a ceramic substrate with a resin material in the manufacturing process of the optical device. FIG. 3 is a schematic cross-sectional view showing a state in which a fitting hole is formed in a resin filling portion in the manufacturing process of the optical device. FIG. 3 is a schematic cross-sectional view showing a state where a VCSEL and a photodiode are mounted on a ceramic substrate in the manufacturing process of the optical device. FIG. 3 is a schematic cross-sectional view showing a state in which a guide pin is fitted into a fitting hole in the manufacturing process of the optical device. FIG. 3 is a schematic cross-sectional view showing a state in which the optical waveguide is fixed while aligning the ceramic substrate and the optical waveguide in the manufacturing process of the optical device. The principal part expansion schematic sectional drawing which shows the test sample of Example 1. FIG. The principal part expansion schematic sectional drawing which shows the test sample of Example 2. FIG. The principal part expansion schematic sectional drawing which shows the test sample of Example 3. FIG. The principal part expansion schematic sectional drawing which shows the test sample of Example 4. FIG. The principal part expansion schematic sectional drawing which shows the test sample of Example 5. FIG. The principal part expansion schematic sectional drawing which shows the test sample of Example 6. FIG. The principal part expansion schematic sectional drawing which shows the test sample of the comparative examples 1 and 2. FIG. The table | surface which shows a test result. The schematic sectional drawing which shows the optical device of 2nd Embodiment provided with an optical fiber connector. The schematic sectional drawing which shows the optical device of 3rd Embodiment provided with an optical fiber connector. The schematic sectional drawing which shows the green sheet before a hole process in the manufacture process of the optical device of another embodiment. The schematic sectional drawing which shows the state which drilled to the upper surface side of the green sheet in the manufacture process of the optical device of another embodiment. FIG. 5 is a schematic cross-sectional view showing a state in which a filling hole is formed by drilling the lower surface side of a green sheet in the manufacturing process of the optical device of another embodiment. The schematic sectional drawing which shows the optical device of another embodiment. The schematic sectional drawing which shows the optical device of another embodiment. The schematic sectional drawing which shows the optical device of another embodiment. FIG. 6 is a schematic cross-sectional view showing a conventional optical device. The principal part expansion schematic sectional drawing for demonstrating the problem in the optical device of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,150 ... Optical component support substrate as a component support substrate 11 ... Ceramic substrate as a substrate 12 ... Upper surface as a first main surface 13 ... Lower surface as a second main surface 14 ... VCSEL as an optical element
DESCRIPTION OF SYMBOLS 16 ... Photodiode as an optical element 21 ... Filling hole 22 ... Resin filling part 23 ... Fitting hole 24 ... Guide pin as a component support 31 ... Optical waveguide as another component (optical component) 36 ... As alignment recessed part Alignment hole 41, 71, 81, 141, 151, 161 ... Optical device 51, 52, 53, 54, 55 ... Ceramic layer 56 ... Green sheet as ceramic unsintered body 57 ... Through hole 58 ... Ceramic laminate DESCRIPTION OF SYMBOLS 61 ... 1st opening part 62 ... 2nd opening part 63 ... Intermediate position 72 ... Optical fiber connector as other components (optical components) 86 ... Optical fiber connector as other components (optical components) 87 ... Other components (optical components) As a microlens array 124,224 ... projection

Claims (9)

A substrate having a first main surface and a second main surface, and having a filling hole having a first opening opening at least in the first main surface;
A resin filling portion disposed in the filling hole and having a fitting hole opened in the first main surface;
It is fixed by being fitted into the fitting hole, and has a component support that can support other components at a location protruding from the fitting hole, and the filling hole has a stepped unevenness on its inner wall surface. The step-shaped unevenness has a height difference of 100 μm or more between a recess on the inner wall surface and a protrusion on the inner wall surface, and has an inner diameter that varies depending on a depth position thereof. Component support board.   The component support board according to claim 1, wherein the filling hole has the largest diameter in the first opening.   The filling hole has a second opening that opens at the second main surface, and has a smallest diameter at an intermediate position between the first opening and the second opening, and the first opening from the intermediate position. The component supporting board according to claim 1, wherein the diameter increases toward the portion and the second opening.   The substrate is a ceramic multilayer substrate composed of a plurality of ceramic layers having through holes, and the filling hole includes a plurality of the through holes, and the first opening and the second from the intermediate position. The component supporting board according to claim 3, wherein the component supporting board has a structure in which the diameter increases stepwise toward the opening.   5. The component support board according to claim 1, wherein a maximum diameter of the filling hole is 1.1 times or more a minimum diameter.   The fitting hole is a precision machined hole, and the component support is fitted to an alignment recess of an optical component having at least one of a light transmission function, a light collecting function, and a light reflection function. 6. The component support board according to claim 1, wherein the component support substrate is a guide pin capable of supporting the optical component. A substrate having a first main surface and a second main surface, and having a filling hole having a first opening opening at least in the first main surface;
A resin filling portion disposed in the filling hole and having a fitting hole that opens at the first main surface, wherein the fitting hole is capable of supporting another component or the other component. A protrusion provided on itself can be fitted, and the filling hole has a stepped unevenness on its inner wall surface, and the stepped unevenness is a recess on the inner wall surface and a protrusion on the inner wall surface. A component support board having a height difference of 100 μm or more and a different inner diameter depending on the depth position . In the manufacturing method of the component support substrate of any one of Claims 1 thru | or 7,
Forming a through hole having a different diameter in a plurality of ceramic unsintered bodies, and making a maximum diameter of the through hole 1.1 times or more a minimum diameter ; and
The ceramic unsintered body with small-diameter through-holes disposed inside, and the ceramic unsintered body with large-diameter through-holes disposed outside, the plurality of ceramic unsintered bodies Laminating and crimping to produce a ceramic laminate having the filling holes,
A firing step of sintering the ceramic laminate to form the substrate;
And a resin filling step of filling the resin material into the filling hole to form the resin filling portion. The component support board according to any one of claims 1 to 5,
An optical element mounted on the component support substrate;
An optical device comprising: an optical component supported by the component support in a state of being aligned with the optical element.

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